GitLab

Implements mojo interactions b/w utility process and browser process for
signaling messenger.
IceConfigFetcher will be implemented along with webrtc medium in upcoming
CLs.

Design doc - go/nearby-chrome-webrtc
Master design doc - go/nearby-chrome

Bug: 1082305
Change-Id: Ia8cb9f3746f781e1ec941925ddbb46d4d9f6300a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2270092
Commit-Queue: Himanshu Jaju <himanshujaju@chromium.org>
Reviewed-by: Alex Chau <alexchau@chromium.org>
Reviewed-by: Alex Gough <ajgo@chromium.org>
Cr-Commit-Position: refs/heads/master@{#784439}